-*- outline -*-

* Structure:

** cls/clsName_2_clsId.db - Relates ClassName to Class Object id.

[className:String]->[clsId:long]

** cls/clsId_2_cls.db - Relates a Class ID to a Class Desc.

[cldId:long]->[classStorageVersion:int][classObject:encoded]

** For each class with stored objects:

*** obj/{objectClassName}/objId_2_obj.db - Stores all objects of a given class.

[objId:long]->[objStorageVersion:int][clsId:long][object:encoded]

*** obj/{objectClassName}/objId_2_objVersion.db - Stores all object mutation serial numbers.

Used to track for colliding transaction.

[objId:long]->[objVersion:long]

** named/objName_2_objId.db - Relates global object identifiers to object ids

[objectName:String]->[objId:long]

*** named/objId_2_objName.db - Inverse.

[objectName:String]->[objId:long]


* Support

** Need GDBM or NDBM binding for Java.  Should implement map interface but for 

** Need encoding and mutation tracking events for Java.

** Package "storage":

*** Store - defines a storage

 /* Public */
 public Store(FilePath place);

 /* Internal */
 public long allocateClsId();
 public void storeClass(Cache cache, long clsId, Class cls);
 public Class loadClass(Cache cache, long clsId);
 public Class loadClass(Cache cache, String name);

 public long allocateObjId();
 public void storeObject(Cache cache, long clsId, Object obj);
 public Object loadObject(Cache cache, long clsId);
 public Object loadObject(Cache cache, String name);

 public ClassEnumerator classes();
 public ObjectEnumerator objects(Class cls);
 public ObjectSubclassEnumerator objectIsa(Class cls);

 public void readLock();
 public void writeLock();
 public long allocateObjId();
 public void storeObject(Cache cache, long objId, Object obj, Cache);
 public Object loadObject(Cache cache, long objId);

*** Enumerator - enumerates objects from a Store

*** ClassEnumerator - enumerates all classes in the system

*** ObjectEnumerator - enumerates all object of a specific class

*** ObjectSubclassEnumerator - enumerates all objects of all subclasses of a class

*** QueryEnumerator - enumerates an enumeration where a specific test is performed

*** Table - defines a key-value table.

 public Table(FilePath place);
 public boolean has(byte[] key);
 public byte[] load(byte[] key);
 public void store(byte[] key, byte[] value);

*** Encoder - encodes an object to a stream.

 public Encoder(OutputStream out, Cache cache); 
 public void writeBoolean(boolean), writeByte(byte ) ... writeDouble()
 public void writeObject(Object obj);

*** Decoder - decodes an object to a stream.

 public Decoder(InputStream out, Cache cache); 
 public boolean readBoolean(), readByte() ... readDouble()
 public Object readObject();

*** Session - manages session with a Store.

 public Session(Store store);

 public Class loadClass(String name);

 public long storeObject(Object obj);
 public long objId(Object obj);
 public Object loadObject(long objId);

 public long storeObject(Object obj, String objName);
 public Object loadObject(String objId);

 public ClassEnumerator classes();
 public ObjectEnumerator objects(Class cls);
 public ObjectSubclassEnumerator objectsIsa(Class cls);

*** Cache - cache objects loaded during a Session.

 private Map objToId = new HashMap(); /* Probably use JNI to speed this up. */
 private Map objIdToObj = new HashMap();

 public Object get(long id);
 public long get(Object obj);
 public void set(long id, Object obj);

*** Transaction - tracks mutations to loaded objects

 private Map obj /* probably use JNI to speed this up. */

 public Transaction(Session session);
 public void abort();
 public void commit();